1. Field of the Invention
The present invention relates to a piezoelectric ceramic and more particularly to a lead-free piezoelectric ceramic and a method for manufacturing the lead-free piezoelectric ceramic. The present invention also relates to a piezoelectric element, a multilayered piezoelectric element, a method for manufacturing a multilayered piezoelectric element, a liquid discharge head, a liquid discharge apparatus, an ultrasonic motor, an optical apparatus, a vibratory apparatus, a dust removing device, an image pickup apparatus, and electronic equipment, each including the piezoelectric ceramic.
2. Description of the Related Art
In general, piezoelectric ceramics are ABO3 perovskite type metal oxides, such as lead zirconate titanate (hereinafter referred to as “PZT”). However, PZT contains lead as an A site element, and its effect on the environment is regarded as a problem. Thus, there is a demand for piezoelectric ceramics of lead-free perovskite type metal oxides.
One known piezoelectric ceramic of a lead-free perovskite type metal oxide is barium titanate. In order to improve the characteristics of barium titanate, materials based on barium titanate are being developed.
Japanese Patent No. 4039029 discloses a piezoelectric ceramic containing barium titanate, wherein the A site of the barium titanate is partly substituted by Ca. Japanese Patent Laid-Open No. 2010-120835 discloses a material containing the piezoelectric ceramic and Mn, Fe, or Cu, wherein the A site of the barium titanate is partly substituted by Ca. These materials have a higher mechanical quality factor than barium titanate but disadvantageously have a poor piezoelectric property.